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Purro SA, Farmer M, Noble E, Sarell CJ, Powell M, Yip D, Giggins L, Zakka L, Thomas DX, Farrow M, Nicoll AJ, Walsh D, Collinge J. Two mouse models of Alzheimer's disease accumulate amyloid at different rates and have distinct Aβ oligomer profiles unaltered by ablation of cellular prion protein. PLoS One 2023; 18:e0294465. [PMID: 37976283 PMCID: PMC10655998 DOI: 10.1371/journal.pone.0294465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 11/02/2023] [Indexed: 11/19/2023] Open
Abstract
Oligomers formed from monomers of the amyloid β-protein (Aβ) are thought to be central to the pathogenesis of Alzheimer's disease (AD). Unsurprisingly for a complex disease, current mouse models of AD fail to fully mimic the clinical disease in humans. Moreover, results obtained in a given mouse model are not always reproduced in a different model. Cellular prion protein (PrPC) is now an established receptor for Aβ oligomers. However, studies of the Aβ-PrPC interaction in different mouse models have yielded contradictory results. Here we performed a longitudinal study assessing a range of biochemical and histological features in the commonly used J20 and APP-PS1 mouse models. Our analysis demonstrated that PrPC ablation had no effect on amyloid accumulation or oligomer production. However, we found that APP-PS1 mice had higher levels of oligomers, that these could bind to recombinant PrPC, and were recognised by the OC antibody which distinguishes parallel, in register fibrils. On the other hand, J20 mice had a lower level of Aβ oligomers, which did not interact with PrPC when tested in vitro and were OC-negative. These results suggest the two mouse models produce diverse Aβ assemblies that could interact with different targets, highlighting the necessity to characterise the conformation of the Aβ oligomers concomitantly with the toxic cascade elicited by them. Our results provide an explanation for the apparent contradictory results found in APP-PS1 mice and the J20 mouse line in regards to Aβ toxicity mediated by PrPC.
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Affiliation(s)
- Silvia A. Purro
- MRC Prion Unit at UCL, Institute of Prion diseases, University College London, London, United Kingdom
| | - Michael Farmer
- MRC Prion Unit at UCL, Institute of Prion diseases, University College London, London, United Kingdom
| | - Elizabeth Noble
- MRC Prion Unit at UCL, Institute of Prion diseases, University College London, London, United Kingdom
| | - Claire J. Sarell
- MRC Prion Unit at UCL, Institute of Prion diseases, University College London, London, United Kingdom
| | - Megan Powell
- MRC Prion Unit at UCL, Institute of Prion diseases, University College London, London, United Kingdom
| | - Daniel Yip
- MRC Prion Unit at UCL, Institute of Prion diseases, University College London, London, United Kingdom
| | - Lauren Giggins
- MRC Prion Unit at UCL, Institute of Prion diseases, University College London, London, United Kingdom
| | - Leila Zakka
- MRC Prion Unit at UCL, Institute of Prion diseases, University College London, London, United Kingdom
| | - David X. Thomas
- MRC Prion Unit at UCL, Institute of Prion diseases, University College London, London, United Kingdom
| | - Mark Farrow
- MRC Prion Unit at UCL, Institute of Prion diseases, University College London, London, United Kingdom
| | - Andrew J. Nicoll
- MRC Prion Unit at UCL, Institute of Prion diseases, University College London, London, United Kingdom
| | - Dominic Walsh
- MRC Prion Unit at UCL, Institute of Prion diseases, University College London, London, United Kingdom
- Laboratory for Neurodegenerative Research, Ann Romney Center for Neurologic Diseases, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - John Collinge
- MRC Prion Unit at UCL, Institute of Prion diseases, University College London, London, United Kingdom
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2
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Wiseman FK, Pulford LJ, Barkus C, Liao F, Portelius E, Webb R, Chávez-Gutiérrez L, Cleverley K, Noy S, Sheppard O, Collins T, Powell C, Sarell CJ, Rickman M, Choong X, Tosh JL, Siganporia C, Whittaker HT, Stewart F, Szaruga M, Murphy MP, Blennow K, de Strooper B, Zetterberg H, Bannerman D, Holtzman DM, Tybulewicz VLJ, Fisher EMC. Trisomy of human chromosome 21 enhances amyloid-β deposition independently of an extra copy of APP. Brain 2019; 141:2457-2474. [PMID: 29945247 PMCID: PMC6061702 DOI: 10.1093/brain/awy159] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 04/18/2018] [Indexed: 01/11/2023] Open
Abstract
Down syndrome, caused by trisomy of chromosome 21, is the single most common risk factor for early-onset Alzheimer's disease. Worldwide approximately 6 million people have Down syndrome, and all these individuals will develop the hallmark amyloid plaques and neurofibrillary tangles of Alzheimer's disease by the age of 40 and the vast majority will go on to develop dementia. Triplication of APP, a gene on chromosome 21, is sufficient to cause early-onset Alzheimer's disease in the absence of Down syndrome. However, whether triplication of other chromosome 21 genes influences disease pathogenesis in the context of Down syndrome is unclear. Here we show, in a mouse model, that triplication of chromosome 21 genes other than APP increases amyloid-β aggregation, deposition of amyloid-β plaques and worsens associated cognitive deficits. This indicates that triplication of chromosome 21 genes other than APP is likely to have an important role to play in Alzheimer's disease pathogenesis in individuals who have Down syndrome. We go on to show that the effect of trisomy of chromosome 21 on amyloid-β aggregation correlates with an unexpected shift in soluble amyloid-β 40/42 ratio. This alteration in amyloid-β isoform ratio occurs independently of a change in the carboxypeptidase activity of the γ-secretase complex, which cleaves the peptide from APP, or the rate of extracellular clearance of amyloid-β. These new mechanistic insights into the role of triplication of genes on chromosome 21, other than APP, in the development of Alzheimer's disease in individuals who have Down syndrome may have implications for the treatment of this common cause of neurodegeneration.
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Affiliation(s)
- Frances K Wiseman
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, WC1N 3BG UK
- The LonDownS Consortium, Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, Denmark Hill, London, SE5 8AF, UK
| | - Laura J Pulford
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, WC1N 3BG UK
| | - Chris Barkus
- Department of Experimental Psychology, University of Oxford, Oxford, OX1 3PH, UK
| | - Fan Liao
- Department of Neurology, Washington University School of Medicine, St Louis, Missouri, 63110, USA
| | - Erik Portelius
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, University of Gothenburg, S-405 30, Sweden
| | - Robin Webb
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, 40507, USA
| | - Lucia Chávez-Gutiérrez
- VIB-KU Leuven Center for Brain and Disease Research, VIB-Leuven 3000, Center for Human Genetics, Universitaire Ziekenhuizen and LIND, KU Leuven, Leuven, Belgium
| | - Karen Cleverley
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, WC1N 3BG UK
| | - Sue Noy
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, WC1N 3BG UK
| | - Olivia Sheppard
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, WC1N 3BG UK
| | - Toby Collins
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, WC1N 3BG UK
| | - Caroline Powell
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, 33 Cleveland Street, London W1W 7FF, UK
| | - Claire J Sarell
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, 33 Cleveland Street, London W1W 7FF, UK
| | - Matthew Rickman
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, WC1N 3BG UK
| | - Xun Choong
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, WC1N 3BG UK
| | - Justin L Tosh
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, WC1N 3BG UK
| | - Carlos Siganporia
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, WC1N 3BG UK
| | - Heather T Whittaker
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, WC1N 3BG UK
| | - Floy Stewart
- Department of Neurology, Washington University School of Medicine, St Louis, Missouri, 63110, USA
| | - Maria Szaruga
- VIB-KU Leuven Center for Brain and Disease Research, VIB-Leuven 3000, Center for Human Genetics, Universitaire Ziekenhuizen and LIND, KU Leuven, Leuven, Belgium
| | - London Down syndrome consortium
- The LonDownS Consortium, Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, Denmark Hill, London, SE5 8AF, UK
| | - Michael P Murphy
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, 40507, USA
| | - Kaj Blennow
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, University of Gothenburg, S-405 30, Sweden
| | - Bart de Strooper
- VIB-KU Leuven Center for Brain and Disease Research, VIB-Leuven 3000, Center for Human Genetics, Universitaire Ziekenhuizen and LIND, KU Leuven, Leuven, Belgium
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, WC1N 3BG, UK
- UK Dementia Research Institute, London, WC2B 4AN, UK
| | - Henrik Zetterberg
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, University of Gothenburg, S-405 30, Sweden
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, WC1N 3BG, UK
- UK Dementia Research Institute, London, WC2B 4AN, UK
| | - David Bannerman
- Department of Experimental Psychology, University of Oxford, Oxford, OX1 3PH, UK
| | - David M Holtzman
- Department of Neurology, Washington University School of Medicine, St Louis, Missouri, 63110, USA
| | - Victor L J Tybulewicz
- The LonDownS Consortium, Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, Denmark Hill, London, SE5 8AF, UK
- Francis Crick Institute, London, NW1 1AT, UK
- Department of Medicine, Imperial College, London, SW7 2AZ, UK
- Correspondence may also be addressed to: Victor Tybulewicz Francis Crick Institute, London, NW1 1AT, UK E-mail:
| | - Elizabeth M C Fisher
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, WC1N 3BG UK
- The LonDownS Consortium, Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, Denmark Hill, London, SE5 8AF, UK
- Correspondence to: Elizabeth Fisher Department of Neurodegenerative Disease UCL Institute of Neurology London, WC1N 3BG UK E-mail:
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Sarell CJ, Quarterman E, Yip DCM, Terry C, Nicoll AJ, Wadsworth JDF, Farrow MA, Walsh DM, Collinge J. Soluble Aβ aggregates can inhibit prion propagation. Open Biol 2018; 7:rsob.170158. [PMID: 29142106 PMCID: PMC5717343 DOI: 10.1098/rsob.170158] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 10/10/2017] [Indexed: 12/12/2022] Open
Abstract
Mammalian prions cause lethal neurodegenerative diseases such as Creutzfeldt–Jakob disease (CJD) and consist of multi-chain assemblies of misfolded cellular prion protein (PrPC). Ligands that bind to PrPC can inhibit prion propagation and neurotoxicity. Extensive prior work established that certain soluble assemblies of the Alzheimer's disease (AD)-associated amyloid β-protein (Aβ) can tightly bind to PrPC, and that this interaction may be relevant to their toxicity in AD. Here, we investigated whether such soluble Aβ assemblies might, conversely, have an inhibitory effect on prion propagation. Using cellular models of prion infection and propagation and distinct Aβ preparations, we found that the form of Aβ assemblies which most avidly bound to PrP in vitro also inhibited prion infection and propagation. By contrast, forms of Aβ which exhibit little or no binding to PrP were unable to attenuate prion propagation. These data suggest that soluble aggregates of Aβ can compete with prions for binding to PrPC and emphasize the bidirectional nature of the interplay between Aβ and PrPC in Alzheimer's and prion diseases. Such inhibitory effects of Aβ on prion propagation may contribute to the apparent fall-off in the incidence of sporadic CJD at advanced age where cerebral Aβ deposition is common.
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Affiliation(s)
- Claire J Sarell
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - Emma Quarterman
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - Daniel C-M Yip
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - Cassandra Terry
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - Andrew J Nicoll
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - Jonathan D F Wadsworth
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - Mark A Farrow
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - Dominic M Walsh
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK .,Laboratory for Neurodegenerative Research, Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - John Collinge
- MRC Prion Unit at UCL, UCL Institute of Prion Diseases, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
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4
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Zhang D, Qi Y, Klyubin I, Ondrejcak T, Sarell CJ, Cuello AC, Collinge J, Rowan MJ. Targeting glutamatergic and cellular prion protein mechanisms of amyloid β-mediated persistent synaptic plasticity disruption: Longitudinal studies. Neuropharmacology 2017; 121:231-246. [PMID: 28390893 DOI: 10.1016/j.neuropharm.2017.03.036] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 03/08/2017] [Accepted: 03/30/2017] [Indexed: 01/09/2023]
Abstract
Alzheimer's disease amyloid-β (Aβ) oligomers are synaptotoxic, inappropriately increasing extracellular glutamate concentration and glutamate receptor activation to thereby rapidly disrupt synaptic plasticity. Thus, acutely promoting brain glutamate homeostasis with a blood-based scavenging system, glutamate-oxaloacetate transaminase (GOT), and blocking metabotropic glutamate 5 (mGlu5) receptor or its co-receptor cellular prion protein (PrP), prevent the acute inhibition of long-term potentiation (LTP) by exogenous Aβ. Here, we evaluated the time course of the effects of such interventions in the persistent disruptive effects of Aβ oligomers, either exogenously injected in wild type rats or endogenously generated in transgenic rats that model Alzheimer's disease amyloidosis. We report that repeated, but not acute, systemic administration of recombinant GOT type 1, with or without the glutamate co-substrate oxaloacetate, reversed the persistent deleterious effect of exogenous Aβ on synaptic plasticity. Moreover, similar repetitive treatment reversibly abrogated the inhibition of LTP monitored longitudinally in freely behaving transgenic rats. Remarkably, brief repeated treatment with an mGlu5 receptor antagonist, basimglurant, or an antibody that prevents Aβ oligomer binding to PrP, ICSM35, also had similar reversible ameliorative effects in the transgenic rat model. Overall, the present findings support the ongoing development of therapeutics for early Alzheimer's disease based on these complementary approaches.
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Affiliation(s)
- Dainan Zhang
- Department of Pharmacology & Therapeutics, and Trinity College Institute of Neuroscience, Trinity College, Dublin 2, Ireland; Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China; Center for Neurological Diseases (NCRC-ND), Beijing, China
| | - Yingjie Qi
- Department of Pharmacology & Therapeutics, and Trinity College Institute of Neuroscience, Trinity College, Dublin 2, Ireland.
| | - Igor Klyubin
- Department of Pharmacology & Therapeutics, and Trinity College Institute of Neuroscience, Trinity College, Dublin 2, Ireland
| | - Tomas Ondrejcak
- Department of Pharmacology & Therapeutics, and Trinity College Institute of Neuroscience, Trinity College, Dublin 2, Ireland
| | - Claire J Sarell
- MRC Prion Unit, Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - A Claudio Cuello
- Department of Pharmacology and Therapeutics, Department of Neurology and Neurosurgery, Department of Anatomy and Cell Biology, McGill University, Montreal, Canada
| | - John Collinge
- MRC Prion Unit, Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Michael J Rowan
- Department of Pharmacology & Therapeutics, and Trinity College Institute of Neuroscience, Trinity College, Dublin 2, Ireland.
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5
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Sarell CJ, Karamanos TK, White SJ, Bunka DHJ, Kalverda AP, Thompson GS, Barker AM, Stockley PG, Radford SE. Distinguishing closely related amyloid precursors using an RNA aptamer. J Biol Chem 2014; 289:26859-26871. [PMID: 25100729 PMCID: PMC4175327 DOI: 10.1074/jbc.m114.595066] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Although amyloid fibrils assembled in vitro commonly involve a single protein, fibrils formed in vivo can contain multiple protein sequences. The amyloidogenic protein human β2-microglobulin (hβ2m) can co-polymerize with its N-terminally truncated variant (ΔN6) in vitro to form hetero-polymeric fibrils that differ from their homo-polymeric counterparts. Discrimination between the different assembly precursors, for example by binding of a biomolecule to one species in a mixture of conformers, offers an opportunity to alter the course of co-assembly and the properties of the fibrils formed. Here, using hβ2m and its amyloidogenic counterpart, ΔΝ6, we describe selection of a 2'F-modified RNA aptamer able to distinguish between these very similar proteins. SELEX with a N30 RNA pool yielded an aptamer (B6) that binds hβ2m with an EC50 of ∼200 nM. NMR spectroscopy was used to assign the (1)H-(15)N HSQC spectrum of the B6-hβ2m complex, revealing that the aptamer binds to the face of hβ2m containing the A, B, E, and D β-strands. In contrast, binding of B6 to ΔN6 is weak and less specific. Kinetic analysis of the effect of B6 on co-polymerization of hβ2m and ΔN6 revealed that the aptamer alters the kinetics of co-polymerization of the two proteins. The results reveal the potential of RNA aptamers as tools for elucidating the mechanisms of co-assembly in amyloid formation and as reagents able to discriminate between very similar protein conformers with different amyloid propensity.
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Affiliation(s)
- Claire J Sarell
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Theodoros K Karamanos
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Simon J White
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - David H J Bunka
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Arnout P Kalverda
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Gary S Thompson
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Amy M Barker
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Peter G Stockley
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom.
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom.
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6
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Su Y, Sarell CJ, Eddy MT, Debelouchina GT, Andreas LB, Pashley CL, Radford SE, Griffin RG. Secondary structure in the core of amyloid fibrils formed from human β₂m and its truncated variant ΔN6. J Am Chem Soc 2014; 136:6313-25. [PMID: 24679070 PMCID: PMC4017606 DOI: 10.1021/ja4126092] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
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Amyloid
fibrils formed from initially soluble proteins with diverse
sequences are associated with an array of human diseases. In the human
disorder, dialysis-related amyloidosis (DRA), fibrils contain two
major constituents, full-length human β2-microglobulin
(hβ2m) and a truncation variant, ΔN6 which
lacks the N-terminal six amino acids. These fibrils are assembled
from initially natively folded proteins with an all antiparallel β-stranded
structure. Here, backbone conformations of wild-type hβ2m and ΔN6 in their amyloid forms have been determined
using a combination of dilute isotopic labeling strategies and multidimensional
magic angle spinning (MAS) NMR techniques at high magnetic fields,
providing valuable structural information at the atomic-level about
the fibril architecture. The secondary structures of both fibril types,
determined by the assignment of ∼80% of the backbone resonances
of these 100- and 94-residue proteins, respectively, reveal substantial
backbone rearrangement compared with the location of β-strands
in their native immunoglobulin folds. The identification of seven
β-strands in hβ2m fibrils indicates that approximately
70 residues are in a β-strand conformation in the fibril core.
By contrast, nine β-strands comprise the fibrils formed from
ΔN6, indicating a more extensive core. The precise location
and length of β-strands in the two fibril forms also differ.
The results indicate fibrils of ΔN6 and hβ2m have an extensive core architecture involving the majority of residues
in the polypeptide sequence. The common elements of the backbone structure
of the two proteins likely facilitates their ability to copolymerize
during amyloid fibril assembly.
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Affiliation(s)
- Yongchao Su
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology Cambridge, Massachusetts 02139, United States
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7
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Abstract
How, and why, different proteins form amyloid fibrils is most often studied in vitro using a single purified protein sequence. However, many amyloid diseases involve co-aggregation of different protein species, including proteins with/without post-translational modifications (e.g., different strains of PrP), proteins of different length (e.g., β₂-microglobulin and ΔN6, Aβ40, and Aβ42), sequence variants (e.g., Aβ and Aβ(ARC)), and proteins from different organisms (e.g., bovine PrP and human PrP). The consequences of co-aggregation of different proteins upon the structure, stability, species transmission and toxicity of the resulting amyloid aggregates is discussed here, including the role of co-aggregation in expanding the repertoire of oligomeric and fibrillar structures and how this can affect their biological and biophysical properties.
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Affiliation(s)
- Claire J Sarell
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology; University of Leeds; Leeds, UK
| | - Peter G Stockley
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology; University of Leeds; Leeds, UK
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology; University of Leeds; Leeds, UK
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8
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Younan ND, Sarell CJ, Davies P, Brown DR, Viles JH. The cellular prion protein traps Alzheimer's Aβ in an oligomeric form and disassembles amyloid fibers. FASEB J 2013; 27:1847-58. [PMID: 23335053 DOI: 10.1096/fj.12-222588] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
There is now strong evidence to show that the presence of the cellular prion protein (PrP(C)) mediates amyloid-β (Aβ) neurotoxicity in Alzheimer's disease (AD). Here, we probe the molecular details of the interaction between PrP(C) and Aβ and discover that substoichiometric amounts of PrP(C), as little as 1/20, relative to Aβ will strongly inhibit amyloid fibril formation. This effect is specific to the unstructured N-terminal domain of PrP(C). Electron microscopy indicates PrP(C) is able to trap Aβ in an oligomeric form. Unlike fibers, this oligomeric Aβ contains antiparallel β sheet and binds to a oligomer specific conformational antibody. Our NMR studies show that a specific region of PrP(C), notably residues 95-113, binds to Aβ oligomers, but only once Aβ misfolds. The ability of PrP(C) to trap and concentrate Aβ in an oligomeric form and disassemble mature fibers suggests a mechanism by which PrP(C) might confer Aβ toxicity in AD, as oligomers are thought to be the toxic form of Aβ. Identification of a specific recognition site on PrP(C) that traps Aβ in an oligomeric form is potentially a therapeutic target for the treatment of Alzheimer's disease.
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Affiliation(s)
- Nadine D Younan
- School of Biological and Chemical Sciences, Queen Mary, University of London, London, UK
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9
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Sarell CJ, Woods LA, Su Y, Debelouchina GT, Ashcroft AE, Griffin RG, Stockley PG, Radford SE. Expanding the repertoire of amyloid polymorphs by co-polymerization of related protein precursors. J Biol Chem 2013; 288:7327-37. [PMID: 23329840 PMCID: PMC3591641 DOI: 10.1074/jbc.m112.447524] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Amyloid fibrils can be generated from proteins with diverse sequences and folds. Although amyloid fibrils assembled in vitro commonly involve a single protein precursor, fibrils formed in vivo can contain more than one protein sequence. How fibril structure and stability differ in fibrils composed of single proteins (homopolymeric fibrils) from those generated by co-polymerization of more than one protein sequence (heteropolymeric fibrils) is poorly understood. Here we compare the structure and stability of homo and heteropolymeric fibrils formed from human β2-microglobulin and its truncated variant ΔN6. We use an array of approaches (limited proteolysis, magic angle spinning NMR, Fourier transform infrared spectroscopy, and fluorescence) combined with measurements of thermodynamic stability to characterize the different fibril types. The results reveal fibrils with different structural properties, different side-chain packing, and strikingly different stabilities. These findings demonstrate how co-polymerization of related precursor sequences can expand the repertoire of structural and thermodynamic polymorphism in amyloid fibrils to an extent that is greater than that obtained by polymerization of a single precursor alone.
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Affiliation(s)
- Claire J Sarell
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
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10
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Davies P, Wang X, Sarell CJ, Drewett A, Marken F, Viles JH, Brown DR. The synucleins are a family of redox-active copper binding proteins. Biochemistry 2010; 50:37-47. [PMID: 21117662 DOI: 10.1021/bi101582p] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Thermodynamic studies in conjunction with EPR confirm that α-synuclein, β-synuclein, and γ-synuclein bind copper(II) in a high affinity 1:1 stoichiometry. γ-Synuclein demonstrates the highest affinity, in the picomolar range, while α-synuclein and β-synuclein both bind copper(II) with nanomolar affinity. The copper center on all three proteins demonstrates reversible or partly reversible redox cycling. Various mutations show that the primary coordinating ligand for copper(II) is located within the N-terminal regions between residues 2-9. There is also a contribution from the C-terminus in conjunction with the histidine at position 50 in α-synuclein and position 65 in β-synuclein, although these regions appear to have little effect on overall coordination stability. These histidines and the C-terminus, however, appear to be critical to the redox engine of the proteins.
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Affiliation(s)
- Paul Davies
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA27AY, UK
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Sarell CJ, Wilkinson SR, Viles JH. Substoichiometric levels of Cu2+ ions accelerate the kinetics of fiber formation and promote cell toxicity of amyloid-{beta} from Alzheimer disease. J Biol Chem 2010; 285:41533-40. [PMID: 20974842 DOI: 10.1074/jbc.m110.171355] [Citation(s) in RCA: 157] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A role for Cu(2+) ions in Alzheimer disease is often disputed, as it is believed that Cu(2+) ions only promote nontoxic amorphous aggregates of amyloid-β (Aβ). In contrast with currently held opinion, we show that the presence of substoichiometric levels of Cu(2+) ions in fact doubles the rate of production of amyloid fibers, accelerating both the nucleation and elongation of fiber formation. We suggest that binding of Cu(2+) ions at a physiological pH causes Aβ to approach its isoelectric point, thus inducing self-association and fiber formation. We further show that Cu(2+) ions bound to Aβ are consistently more toxic to neuronal cells than Aβ in the absence of Cu(2+) ions, whereas Cu(2+) ions in the absence of Aβ are not cytotoxic. The degree of Cu-Aβ cytotoxicity correlates with the levels of Cu(2+) ions that accelerate fiber formation. We note the effect appears to be specific for Cu(2+) ions as Zn(2+) ions inhibit the formation of fibers. An active role for Cu(2+) ions in accelerating fiber formation and promoting cell death suggests impaired copper homeostasis may be a risk factor in Alzheimer disease.
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Affiliation(s)
- Claire J Sarell
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, United Kingdom
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Sarell CJ, Syme CD, Rigby SEJ, Viles JH. Copper(II) binding to amyloid-beta fibrils of Alzheimer's disease reveals a picomolar affinity: stoichiometry and coordination geometry are independent of Abeta oligomeric form. Biochemistry 2009; 48:4388-402. [PMID: 19338344 DOI: 10.1021/bi900254n] [Citation(s) in RCA: 178] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cu(2+) ions are found concentrated within senile plaques of Alzheimer's disease patients directly bound to amyloid-beta peptide (Abeta) and are linked to the neurotoxicity and self-association of Abeta. The affinity of Cu(2+) for monomeric Abeta is highly disputed, and there have been no reports of affinity of Cu(2+) for fibrillar Abeta. We therefore measured the affinity of Cu(2+) for both monomeric and fibrillar Abeta(1-42) using two independent methods: fluorescence quenching and circular dichroism. The binding curves were almost identical for both fibrillar and monomeric forms. Competition studies with free glycine, l-histidine, and nitrilotriacetic acid (NTA) indicate an apparent (conditional) dissociation constant of 10(-11) M, at pH 7.4. Previous studies of Cu-Abeta have typically found the affinity 2 or more orders of magnitude weaker, largely because the affinity of competing ligands or buffers has been underestimated. Abeta fibers are able to bind a full stoichiometric complement of Cu(2+) ions with little change in their secondary structure and have coordination geometry identical to that of monomeric Abeta. Electron paramagnetic resonance studies (EPR) with Abeta His/Ala analogues suggest a dynamic view of the tetragonal Cu(2+) complex, with axial as well as equatorial coordination of imidazole nitrogens creating an ensemble of coordination geometries in exchange between each other. Furthermore, the N-terminal amino group is essential for the formation of high-pH complex II. The Abeta(1-28) fragment binds an additional Cu(2+) ion compared to full-length Abeta, with appreciable affinity. This second binding site is revealed in Abeta(1-42) upon addition of methanol, indicating hydrophobic interactions block the formation of this weaker carboxylate-rich complex. A Cu(2+) affinity for Abeta of 10(11) M(-1) supports a modified amyloid cascade hypothesis in which Cu(2+) is central to Abeta neurotoxicity.
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Affiliation(s)
- Claire J Sarell
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
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